Restrictive factors of the measurement accuracy to estimate Blood Pressure with Pulse wave Transit Time

Pulse wave Transit Time (PTT) is a promising approach to achieve a continuous and non-invasive measurement of Blood Pressure (BP). However, compared with invasive and cuff-based methods, the PTT-based method is not accurate enough for some circumstances. In this paper, its major restrictive factors are investigated. According to the experimental results and analysis, the breathing rhythm and movement of subjects have an adverse impact on the detection of the pulse wave. In order to obtain better signals, noise should be eliminated and the time delay resulting from filters should be considered. The validity of PTT detection is a dominating factor of accuracy as well. Furthermore, the measured PTT is not the real PTT from the physiological perspective, which is mainly due to the acquisition difficulty of the pulse wave from the main artery. Finally, the influence of the regulatory mechanism is also analyzed.